Silvia Achia Nieuwenburg, Vita Willemijn Jongen, Maarten Schim van der Loeff, Henry de Vries, Alje van Dam
{"title":"Seroconversion in syphilis screening without positive confirmatory tests points at early infection.","authors":"Silvia Achia Nieuwenburg, Vita Willemijn Jongen, Maarten Schim van der Loeff, Henry de Vries, Alje van Dam","doi":"10.1136/sextrans-2023-055973","DOIUrl":null,"url":null,"abstract":"<p><strong>Introduction: </strong>The chemiluminescence immunoassay (CLIA) is a widely used screening test for syphilis. A CLIA seroconversion in the absence of a positive line immunoassay (LIA) or rapid plasma reagin (RPR) could indicate either an early incubating syphilis or a false positive result. We aimed to evaluate the diagnostic value of such seroconversions.</p><p><strong>Methods: </strong>We retrospectively analysed data of clients visiting the Centre for Sexual Health Amsterdam between July 2013 and August 2021 with a positive CLIA and a negative RPR and negative or indeterminate LIA (at time T<sub>o</sub>), and a preceding visit (T<sub>-1</sub>) with a negative CLIA <6 months of T<sub>o</sub> ('unconfirmed CLIA seroconversion'). If available, data of follow-up visits (T<sub>1</sub>) <2 months of T<sub>o</sub> were also included. A syphilis diagnosis was confirmed if darkfield microscopy or PCR for <i>Treponema pallidum</i> was positive at T<sub>0</sub> or T<sub>1</sub>, or if RPR and/or LIA were positive at T<sub>1</sub>.</p><p><strong>Results: </strong>We included data of 107 clients with unconfirmed CLIA seroconversion. The value of CLIA seroconversion could not be established in 13 (12.1%) clients. In the remaining 94 clients, the unconfirmed CLIA seroconversion was confirmed as early syphilis in 72 (76.6%) clients and probable syphilis in 6 (6.4%) clients. In 16 (17.0%) clients, the unconfirmed CLIA seroconversion was regarded as a false positive reaction of whom 4 (5.3%) clients had a seroreversion of the CLIA at T<sub>1</sub>.</p><p><strong>Conclusion: </strong>The majority of unconfirmed CLIA seroconversions represented early syphilis infections. Therefore, additional <i>T. pallidum</i> PCR, a follow-up consultation or early treatment is recommended.</p>","PeriodicalId":21624,"journal":{"name":"Sexually Transmitted Infections","volume":null,"pages":null},"PeriodicalIF":3.6000,"publicationDate":"2024-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Sexually Transmitted Infections","FirstCategoryId":"3","ListUrlMain":"https://doi.org/10.1136/sextrans-2023-055973","RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"INFECTIOUS DISEASES","Score":null,"Total":0}
引用次数: 0
Abstract
Introduction: The chemiluminescence immunoassay (CLIA) is a widely used screening test for syphilis. A CLIA seroconversion in the absence of a positive line immunoassay (LIA) or rapid plasma reagin (RPR) could indicate either an early incubating syphilis or a false positive result. We aimed to evaluate the diagnostic value of such seroconversions.
Methods: We retrospectively analysed data of clients visiting the Centre for Sexual Health Amsterdam between July 2013 and August 2021 with a positive CLIA and a negative RPR and negative or indeterminate LIA (at time To), and a preceding visit (T-1) with a negative CLIA <6 months of To ('unconfirmed CLIA seroconversion'). If available, data of follow-up visits (T1) <2 months of To were also included. A syphilis diagnosis was confirmed if darkfield microscopy or PCR for Treponema pallidum was positive at T0 or T1, or if RPR and/or LIA were positive at T1.
Results: We included data of 107 clients with unconfirmed CLIA seroconversion. The value of CLIA seroconversion could not be established in 13 (12.1%) clients. In the remaining 94 clients, the unconfirmed CLIA seroconversion was confirmed as early syphilis in 72 (76.6%) clients and probable syphilis in 6 (6.4%) clients. In 16 (17.0%) clients, the unconfirmed CLIA seroconversion was regarded as a false positive reaction of whom 4 (5.3%) clients had a seroreversion of the CLIA at T1.
Conclusion: The majority of unconfirmed CLIA seroconversions represented early syphilis infections. Therefore, additional T. pallidum PCR, a follow-up consultation or early treatment is recommended.
期刊介绍:
Sexually Transmitted Infections is the world’s longest running international journal on sexual health. It aims to keep practitioners, trainees and researchers up to date in the prevention, diagnosis and treatment of all STIs and HIV. The journal publishes original research, descriptive epidemiology, evidence-based reviews and comment on the clinical, public health, sociological and laboratory aspects of sexual health from around the world. We also publish educational articles, letters and other material of interest to readers, along with podcasts and other online material. STI provides a high quality editorial service from submission to publication.